issn: 2454-1362, a case study ... · pdf filea case study on stress analysis of nozzle ......

Imperial Journal of Interdisciplinary Research (IJIR) Vol-2, Issue-9, 2016 ISSN: 2454-1362, http://www.onlinejournal.in

Imperial Journal of Interdisciplinary Research (IJIR) 741

A Case Study on Stress Analysis of Nozzle

Fitted On Pressure Vessel

Nilam B. Bankar1, P. Swaminathan

2& M.S.Lohate

3

1PG Student (M.E.),

2Assistant Professor

1,2Department of Mechanical Engineering, M.P.G.I. College of Engineering.

3PG Student (M.E.), Department of Mechanical Engineering, S.R.E.S College of Engineering

Abstract - The purposeofFEA is to find level of

stresses in the Nozzleand pressure Vessel. Due to

different geometrical profile of pressure vessel &

nozzle joints causes poor profile of the pressure

vessel & nozzle results into discontinuity of cross

section.Due to sudden changes of cross section there

may be a stress concentration creatednear inlet&

outlet connections which results into failure of

junction nearby joints due tostresses created

nearbythe nozzle & pressure vessel junction area

[4].

On the periphery of a pressure vessel if nozzles are

placed, then there may be chances ofunsymmetrical

formation of the nozzle & pressure vessel. Due tothe

unsymmetricalform eccentricity formation in the

system.Due to eccentricity formation, generation of a

couple in the system takes place, which results into

structural imbalance of system [4]. The eccentricity

formation due to single Nozzle used in the pressure

vessel, what will be result if numbers of nozzle used

in pressure vessel[4]. So that the system needs to

carefully analyze with the FEAanalysis software to

study on stress level in the nozzle & pressure vessel.

The main purpose of this study is to determine

thevalue of stresses in thenozzle. The FEA Analysis is

to be conducted as per ASME Section VIII, division

2, part 5.2.

Key Words: Eccentricity, Pressure Vessel, ASME

CODE, FEA.

1. INTRODUCTION To satisfy certain functional requirement opening is

necessary in a pressure vessel such as inlet or outlet

connection, drains,vents & manholes etc [1]. If

geometrical construction of pressure vessel &nozzle

connections significantly vary even in one pressure

vessel, then discontinuity formation of the pressure

vessel shell.Due to discontinuity stress concentration

is created nearby opening of pressure vessel and then

there may be more chances of junctionfailure due to

high stresses created around the junction area [5].On

the periphery of a pressure vessel if nozzles are

placed, thenthe axis symmetry of the pressure vessel

& nozzle is disturb and it causes

eccentricityformation in system.Most of time

thismay cause formation of a couple, which results

into a structural imbalance of system takes place.

Due to use of singlenozzle causes an

eccentricityformation, what will be the result if

numberof nozzles used in a pressure vessel.So it is

necessaryto analyse the system with the help of FEA

analysis to obtain effects on nozzle due to Stresses

created on thepressure vessel. The stress analysis of

vessel is always a critical & a serious issue [5]. The

internal pressure of vesselis used in the structural

analysis of the system when pressure vessel is in

working condition. The external forces and moments

applied to nozzle are also considered. External

loading applied by a weight of piping system

attached to the nozzle&to obtain the Value of load

level and moment by an analysis of nozzle location

& piping system. Number of research works

including analytical, experimental & FEA Analysis

have been developed for stress analysis of nozzle

connection in pressure vessel. The various code of

the system which does not provides any procedure to

calculate the exact value of stresses but only suggest

a procedure how to design the junction area between

nozzle & pressure vessel [10].

Therefore it needs to carry out a detailed FEA

analysis work to calculate stresses aroundjunction

between pressure vessel & nozzle.

2. PROBLEM STATEMENT &

OBJECTIVES

On the periphery of a pressure vessel if nozzles

are placed, then there may be discontinuity formation

in pressure vessel. Due to unsymmetrical,

eccentricity formation in the system. Due to

eccentricity formation, generation of couple takes

place. Which results into structural imbalance of

system [7].The single Nozzle is going to cause an

eccentricity.What will happen if there are numbers of

nozzle attached to the pressure vessel. Therefore

analyzing in FEA analysis to get effects of nozzle on

Stress attributes of the vessel. The real world

experience can be modeled in Finite Element

Analysis [3].The main goal of this study is to get

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Imperial Journal of Interdisciplinary Research (IJIR) Page 1742

accurate results by comparing the analytical results

with the help of Lame’s equation & FEA results.

2.1 Necessity

To avoid pressure vessel rupture failure due to

stresses created in pressure vessel.It is necessary to

identify the main contributed factorsto stress

development in anozzle & a pressure vessel and how

they can be reduced. This work presents design work

analysis of a stress development factors using 3D

CAD models& analysis softwarein nozzle &pressure

vessels assembly and with given operating pressure

various stress and deformation plot by finite element

engineering simulation program.

2.2 Objective of Work 1. With the help of CAD software to Create 3D

model of pressure vessel & nozzle and to

carried out study for given condition of pressure

vessel

2. For the purpose of internal design model of

nozzle and pressure are analysed with given

conditions

3. FEA analysis is performed according to ASME

code Section VIII, Division 2

4. To find out the valueof stress in the Nozzle N-12

of liquidCarbon drain Pressure Vessel.

3. ANALYTICAL FORMULA Hoop stress or circumferential stressin the shell away

from discontinuity can becalculated with the help of

Lame’s equation. The calculations for stress due to

pressure are as follows,

𝜎𝜙 =𝑃𝑥𝑅𝑖

2

𝑅𝑜2 − 𝑅𝑖

2 1 +

𝑅𝑜2

𝑅𝑖2

Where,

Ro = Outer radius of shell, mm.

R i = Inner radius of shell, mm.

P = 0.35MPa (Internal pressure)

3.1 For Nozzle N12:

To find out the value of stress due to internal

pressure take the dimensions of nozzle as follow

Outer Diameter = 60.33 mm

Thickness = 8.738 mm

Ro = 30.165 mm

Ri = 21.427 mm

P = 0.35 N/mm2

𝜎𝜙 =0.35𝑥106𝑥21.4272

30.1652 − 21.4272 1 +

30.1652

21.4272

By calculating the above equation values we get,

𝜎𝜙= 1.05595 x 106 Pa

σ𝜙= 1.05595MPa

4. FEA VALIDATION Stress analysis of complicated shapes is very difficult

by Photo elasticity process instead of that Stress

analysis by FEM is better choice. So FEA Analysis

isselected for stress analysis purpose. FEA Analysis

by Ansys software is one of the popular software

used for FEA Validation. The mainobjective of

analysis is to find stress values in nozzles of pressure

vessel per ASME code section VIII Div-2. The study

is conducted for to determine stress value in nozzles

to a definite prescribed level of accuracy. The FEA

Analysis study is conducted with the help of

followingmethodology. A 3D model of a pressure

vessel with fitted nozzles is created by using CAD

software.

4.1 2D Solid Work Model of Pressure

Vessel with fitted Nozzle The 2D solid work modelof pressurevessel with

fitted Nozzle is shown in figure. Consider Nozzle N-

12 for analysis,

Fig -1: 2D solid work model of pressure vessel with

fitted nozzle

4.2 3D Model

The 3D solid work model ofLiquid carbon pressure

vessel is created in CADsoftware and that 3D CAD

Model importedin ansys model as shown,

N1 N12 N13

N4





Fig -2: 3D ANSYSModel

4.33D Mesh Model Meshing is nothing but discretization of object into

the small number of parts is called as elements. Fig.

shows 3D meshed model of Hydro carbon pressure

vessel.

Fig -3: 3D Mesh Model

4.4 Boundary Conditions:

Apply the Boundary conditions on a pressure vessel

and nozzles for validating thestress in nozzle of

apressure vessel. Working Pressure, Force and

Moments applied on nozzle N-12 of pressure vessel

and results are obtained as follows,

Fig -4: Working Internal Pressure plot

Fig -5: Force & Moment Plot for N-12

4.5 Equivalent Stress Plot

By evaluating a shell element through FEA Analysis,

Equivalent stress in a shell element is shown below,

Fig -6: Equivalent Stress Plot

4.6 Normal Stress

Normal stress plot for nozzle N-12 is as shown in

figure.

Fig -7: Normal Stress Plot

5. RESULT AND DISCUSSION By using Analytical equation we can easily calculate

the exact numerical value of stress created in nozzle

of a vessel. With the help of numerical





equation,mathematical results of a pressure vessel are

compared then compared with FEA analysis results.

Thus, FEA Analysis is used for evaluating the stress

level in the nozzle of pressure vessel with more

accuracy.

5.1 Analytical Result Circumferential stress or Hoop stress in Nozzle N-12

away from discontinuity is calculated as,

𝝈𝝓= 1.05595 x 106 Pa........ (i)

5.2 Finite Element Analysis Result Normal stress in nozzle (N-12) away from

discontinuity is evaluated by FEA Analysis with the

help of Analysis software as shown in figure,

𝝈𝝓 = 1.0852 x 106 Pa ........(ii)

The above results are regarding with nozzle N-12,

the same procedure we can take for calculating the

stress level in nozzle N-1, N-4& N-13. By using

Mathematical formula, the stress level in a nozzle

section can be calculated by using analytical equation

and results then validated through FEA Analysis

software.

6. CONCLUSION In this way a case study is to be performed on nozzle

fitted on pressure vessel for stress analysis to be

carried out as per the ASME code&from this analysis

it is concluded that Analytical calculations &FEA

Analysis results are approximately same. The

purpose of analysis is to find out accurate& reliable

results with the help of analysis software & to find

out different Analytical & FEA Analysis methods

using 3D solid work modeling software and post-

processing methods for analysis of nozzle which is

fitted on pressure vessels according to ASME codes.

From this analysis, the mechanical design of a

Nozzle &pressure vessel can be easily verified by a

third party organization to ensure the quality of a

pressure vessel system that it can be easily fulfills the

requirement of the ASME code.

REFERENCES [1] Shyam R Gupta, Ashish Desai,“Optimize

Nozzle Location For Minimization Of Stress In

Pressure Vessel”, IJIRST–International Journal

for Innovative Research in Science &

Technology| Vol. 1, Issue 1, ISSN(online):

2349-6010, June 2014.

[2] Lijing Wen, Chao Guo, Tieping Li,

Chunming Zhang, “Stress Analysis for Reactor

Coolant Pump Nozzle of Nuclear Reactor

Pressure Vessel” Journal of Applied

Mathematics and Physics, 2013, 1, 62-64

Published Online November 2013.

[3] Dharmit Thakore,“Finite Element Analysis of

Pressure Vessel and Nozzle Junction” Revision:

0,Date: 29 March 2013.

[4] Pravin Narale, Prof. P. S. Kachare, “Structural

Analysis of Nozzle Attachment on Pressure

Vessel Design” International Journal of

Engineering Research and Applications (IJERA)

ISSN: 2248-9622 www.ijera.com Vol. 2, Issue4,

July-August 2012, pp.1353-1358.

[5] Sanket S. Chaudhari & D.N. Jadhav, “A

Suggested Stress Analysis Procedure For Nozzle

To Head Shell Element Model – A Case

Study”,International Journal on Theoretical and

Applied Research in Mechanical Engineering

(IJTARME) ISSN : 2319 – 3182, Volume-1,

Issue-2, 2012.

[6] Erik Bjarkby, “Parameterized model for stress

analysis of nozzles”, 2011

[7] A. Hardik B. Nayak and B. R. R. Trivedi,

“Stress Analysis of Reactor Nozzle to Head

Junction” Institute Of Technology, Nirma

University, Ahmedabad – 382 481, 08-10

December, 2011





December, 2011.





December, 2011.

[10] M. A. Nalawade, S. H. Dwivedi, etl., “Analysis

of STHE to Identify Low Stress Area for

Locating Nozzle Opening”IOSR Journal of

Mechanical and Civil Engineering (IOSR-

JMCE) ISSN(e) : 2278-1684, ISSN(p) : 2320–

334X, PP : 44-49.

[11] A Alper Ozalp, “Numerical analysis of choked

converging nozzle flows with surface roughness

and heat flux conditions”Sadhana Vol. 31, Part

1, February 2006, pp. 31–46.

[12] M. Giglio, “Fatigue analysis of different types

of pressure vessel nozzle”International Journal

of Pressure Vessels and Piping 80,

www.elsevier.com/locate/ijpvp (2003) 1–8.



issn: 2454-1362, a case study ... · pdf filea case study on stress analysis of nozzle ......

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